THE FUEL OF THE SUN. 29 



chine, or the vapors and projectiles of a terrestrial volcanic 

 eruption. 



I need scarcely add that this exactly describes the actual- 

 ly-observed results of the recent observations on the corona, 

 and that all the phenomena of this great solar mystery are 

 but necessary and predicable results of the constitution I 

 ascribe to the sun. 



There is a method of manufacturing hypotheses which 

 has become rather prevalent of late, especially among 

 mathematicians, who take observed phenomena, and then 

 arbitrarily and purely from the raw material of their own 

 imagination construct explanatory atoms, media, and ac- 

 tions, which are shaved and pared, scraped and patched, 

 lengthened and shortened, thickened and narrowed, till 

 they are made to fit the phenomena with mathematical ac- 

 curacy. These laborious creations are then put forth as 

 philosophical truths, and, afterwards, the accuracy of their 

 fitting to the phenomena is quoted as evidence of the posi- 

 tive reality of the ethers, atoms, undulations, gyrations, 

 collisions, or whatever else the mathematician may huve 

 thus skilfully created and fitted. It appears to me that 

 such fitness only proves the ingenuity of the fitter the 

 skill of the mathematician and that all such hypotheses 

 belong to the poetry of science; they should be distinctly 

 labelled as products of mathematical imagination, and no- 

 wise be confounded with objective natural truths. Such 

 products of the imagination of the expert may assist the 

 imagination of the student in comprehending some phe- 

 nomena, just as "Jack Frost" and "Billy Wind" may 

 represent certain natural forces to babies ; but if Jack 

 Frost, Billy Wind, electric and magnetic fluids, ultimate 

 atoms, interatomic ethers, nervous fluids, etc., are allowed 

 to invade the intellect, and are accepted as actual physical 

 existences, they become very mischievous philosophical 

 superstitions. 



I make this digression in order to repudiate any partici- 

 pation in this kind of speculation. .Though "The Fuel of 

 the Sun" is avowedly a very bold attempt to unravel majestic 

 mysteries, I have not sought to elucidate the known by means 

 of the unknown, as do these inventors of imaginary agents, 



